- Wine frothing through the airlock.
This can occur when the fermenting vessel is too full. It is always necessary to leave adequate head space to accommodate the frothing found in the early stages of
fermentation. Frothing will subside in a few days. Meanwhile, avoid shaking the jar or vessel and if you have a slightly
cooler place, move the wine there, but do not cool the wine too much as this could cause a “stuck” fermentation.
Clean the outside of the jar and remove and wash the
airlock before replacing. Standing the jar on a tray and placing a plastic bag over the airlock, securing it round the neck of the jar will all help reduce mess.
- Bubbles pass the wrong way through the airlock.
Usually this is a sign that the wine is not fermenting - though it may have finished - See fermentation has already finished.
Temperature variation can cause air to be sucked back into the fermenting vessel.
- Hydrometer reading increasing.
The must (liquid) is incompletely mixed. Dense syrup of sugar and/or improperly mixed concentrate has settles at the bottom of the jar. Stir the jar again to ensure a
thorough mixing of ingredients.
- Mould growing on surface.
If fermentation does not start, eventually particles of mould, which can be a number of colours, will start to grow on the surface. By the time this happens, the must (liquid)
is contaminated and should be thrown away.